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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.commons.rng;
18  
19  /**
20   * Applies to generators whose internal state can be saved and restored.
21   *
22   * @since 1.0
23   */
24  public interface RestorableUniformRandomProvider extends UniformRandomProvider {
25      /**
26       * Saves the state of a generator.
27       *
28       * @return the current state of this instance. It is a value that can
29       * subsequently be passed to the {@link #restoreState(RandomProviderState)
30       * restore} method.
31       * @throws UnsupportedOperationException if the underlying source of
32       * randomness does not support this functionality.
33       */
34      RandomProviderState saveState();
35  
36      /**
37       * Restores the state of a generator.
38       *
39       * @param state State which this instance will be set to.
40       * This parameter would usually have been obtained by a call to
41       * {@link #saveState() saveState} performed either on the same
42       * object as this one, or an object of the exact same class.
43       * @throws UnsupportedOperationException if the underlying source of
44       * randomness does not support this functionality.
45       * @throws IllegalArgumentException if it was detected that the
46       * {@code state} argument is incompatible with this instance.
47       */
48      void restoreState(RandomProviderState state);
49  }